Inertia controlled safety device



Oct. 28, 1947.

J. B. GLENNON ETAL INERTIA CONTROLLED SAFETY DEVICE Filed Oct. 4, 1943 3 Sheets-Sheet l gjwubwtiow 27 2 J. B. GLENNON R. WuWALLAGE B. WOODWARD JR.

Oct. 28, 1947. B: GLENNON ETAL 2,429,515

INERTIA CQNTROLLED SAFETY DEVICE Filed Oct. 4, 1943 3 Sheets-Sheeti 62 uni J. B. GLEN R. W. WALL B. WOODWARD JR.

Oct. 28, 1947. J. B.- GLENNON ETAL 2,429,615

INERTIA CONTROLLED SAFETY DEVICE Filed Oct. 4, 1943 3 Sheets-Sheet 3 Io 4 l5 2 L' g- 3;

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W ff ifi i atented Oct. 28, 1947 INERTIA CGNTROLLED SAFETY DEVICE James B. Glennon,

United States Navy, Roger W. Wallace, United States Army,

and Bernard Woodward, J12, Washington, D. C. Application October 4, 1943, Serial No. 504,862

' 14 Claims.

(Granted under the act amended April 30, 1928;

This invention relates to an inertia controlled safety device for use with a marine mine of the type adapted to be planted within a body of water from an aircraft in flight. More specifically, the invention relates to an inertia controlled safety and arming device in which means are employed to prevent the movement of a detonator into operative relation with respect to an explosive booster charge in the event that the arming plugs of the mine are removed While the mine is on the ground or a short distance therefrom and a violent shock is received before suliicient time has elapsed for the detonator to be moved to the extended position thereof, the device also including means controlled by the inertia element for preventing the closure of a firing circuit to the detonator until the mine receives a violent shock or blow corresponding to the impact of the mine against the surface of the water or against terra firma, as the case may be.

Various devices and arrangements have heretoiore been devised for arming a mine and for extending the detonator into operative position with respect to the explosive charge. In these arrangements it is the usual practice to employ the pressure of the water within which the mine is launched for actuating the detonator to the extended position and to arm the mine under control of a separate arming mechanism. Such arrangements depend for their successful operation upon the establishment of certain connections therebetween which are completed during the assembly of the mine and the mine may, therefore, be rendered fully or in part ineffective by carelessness or inadvertence on the part of the workers during the assembly of the mine in failing to establish the proper connections between the various elements.

This difficulty has been overcome by providing a single detachable unitary structure adapted to be tested through a cycle of operations before the device is assembled within the casing of the mine in which the mine is rendered absolutely safe prior to and during the launching thereof by reason of the provision of certain detachable safety devices including a pair of arming plugs or caps secured respectively to a pair of arming Wires and a detachable arming lever which are required to be removed before the mechanism is started through an arming cycle. A mechanism of this type suitable for use with the present invention is disclosed and claimed in the copende ing application of James B. Glennon and Roger W. Wallace for Arming and firing control mechaof March 3, 1883, as

nism for a marine mine, Serial No. 458,146, filed September 12, 1942, in which the removal of the arming lever as the mine falls away from the aircraft in flight causes the detonator to be unlocked from the fully retracted position thereof, and the removal of the arming plugs causes the spring driven extender mechanism to be set into operation to move the detonator to an extended position in operative relation with respect to the explosive charge Within a predetermined period of time controlled by an escapement mechanism. When the detonator is fully extended, the detonator extender element is disconnected from the escapement mechanism whereby the escapement mechanism continues to operate and thereby cause a pair of arming contacts to be closed in time delayed relation with respect to the in sertion of the detonator within the explosive charge. The mine is not armed, however, until the pair of switch contacts controlled by the inertia element of the present invention are moved to closed position, as will hereinafter more clearly appear as the description proceeds.

In accordance with the present invention, the inertia controlled safety device comprises an inertia operated element adapted to prevent the detonator from moving into the armed or extended position thereof in the event that the inertia element is operated within a predetermined period of time aiter the arming plugs have been removed from the mine corresponding to a period of time less than the time required for the detonator to be moved by the extender mechanism to the extended position. Furthermore, in the event that the extender has been moved to the extended position prior to the operation of the inertia safety device, the operation of the safety device causes a locking member to be moved into the path of travel of the detonator thereby locking the detonator in the extended position by means exclusive of the detonator extending mechanism.

One of the objects of the present invention is the provision of new and improved means for preventing the premature explosion of a mine after the arming plugs are removed therefrom until a predetermined period of time has elapsed and the mine has received a violent shock.

Another object is the provision of new and improved means for preventing the detonator of a mine moving into operative relation with respect to an explosive booster charge when a violent shock or blow is received within a predetermined period of time after the arming plugs have been removed therefrom.

Another object is the provision of an inertia controlled device for a mine having means settable at will to different settings corresponding respectively to different values of force required to operate the inertia element thereof.

Another of the objects is the provision of new and improved means for rendering the mineunresponsive to a shock or blow until the detonator extender mechanism has been set in operation for a period of time suflicient for the detonator to be moved from the fully retracted position thereof.

Still another object is to provide inertia controlled means for closing in part the firing circult of a mine during the movement of the detonator toward the extended position thereof in which the detonator is arrested before reaching the extended position in the event that a shock is received within a predetermined period of time after the arming plugs are removed.

A further object is to provide a new and improved safety device for a mine which is eifective during the handling, transportation, and planting of the mine and in which a heavy blow or shock must be received after the arming plugs have been removed as a prerequisite condition to the firing of the mine;

A still further object is the provision of an inertia controlled safety and arming device for a mine which is economical to manufacture, reliable in operation and which possesses all the desired qualities of ruggedness and durability in service.

Further objects and advantages will appear as the description of the invention and the particular physical embodiments selected to illustrate the invention progresses, and the novel features will be particularly pointed out in the appended claims.

In describing the invention in detail, and the particular physical embodiments selected to illustrate the invention, reference will be had to the accompanying drawings and the several views thereon in which like characters of reference are employed to designate like parts throughout the several views, and in which:

Fig. 1 is a view partially in section and partially in elevation of the inertia controlled device and detonator extending mechanism in accordance with a preferred embodiment of the present invention showing the device in an unoperated condition and the detonator in the retracted position;

Fig. 2 is a view similar to Fig. 1 and partially broken away showing the inertia controlled device in an operated condition and the detonator moved away from the retracted position thereof; Fig. 3 is an enlarged sectional view taken along ,line 33 of Fig. 1;

Fig, 4 is an enlarged detailed sectional view taken substantially along the line 5- 3 of Fig. 1;

Fig. 5 is an enlarged sectional view taken substantially along the line 5-5 of Fig. l;

Fig. 6 is a view similar to Fig. 5 showing the inertia switch contacts in an operated condition;

Fig, 7 is a detailed view in perspective of one of the inertia control elements;

Fig. 8 is a detailed view in perspective of the contact actuating and detonator locking member;

Fig. 9 is a detailed view in perspective of the cam controlled locking plunger employed with the device; and

Fig. 10 shows in diagrammatic form a circuit arrangement suitable for use with the present invention.

Referring now to the drawings for a more complete understanding of the invention and more particularly to Fig. 1 thereof there is shown thereon a detonator extending and arming mechanism indicated generally by the numeral I!) supported by a cap I I adapted to be secured in any suitable manner in the casing of a mine such, for example, as a marine mine adapted to be planted from an aircraft in flight, in which the mine is sufficiently heavy to come to rest on the bed of a body of water within which the mine is planted, the mechanism I 0 preferably being disposed within the casing with the detonator arranged transversely with respect to the line of flight or path of travel of the mine.

The detonator extending and arming mechanism I i! and the cap II are generally similar to the arming and firing control mechanism described and claimed in the copending application of James B. Glennon and Roger W. Wallace for Arming and firing control mechanism for a marine mine, Serial No. 458,146, filed September 12, 1942, and only suflicient of the arming and firing control mechanism, therefore, is described herein as will enable one skilled in the art to which the present invention pertains to understand the present invention.

Pivotally secured to the cap I I as by the pin I2 is a release arm I 3 adapted to be released by one of the arming wires secured to the aircraft as the mine falls away from the aircraft in flight. When this occurs the lock members I l are disengaged from the extender rack I5 and the rack is moved downwardly or inwardly by the spring driven motor comprising the spring I 6 secured at one end thereof to the shaft I! and at the other end to the stud I 3 attached to the plate I9, a gear 2I secured to the shaft and in mesh with the teeth 22 on the rack I5 being employed for establishing an operating connection between the motor and the rack.

The lower end of the plate I9 is formed as at 23 and secured to a circular support 24 as by the screws 25. The support 24 is provided with a centrally arranged aperture within which is disposed one end of a tubular member 26 secured to the circular support as by the screws 2'? and to the plate I9 by the screws 28. Slideably arranged within the member 26 is a plunger 29 adapted to support an electroresponsive detonating device L I having a pair of flexible conductors S2 and 33 connected thereto and passing through a slot 34 within the member 26 thereby to establish an external connection to the detonator without interfering with the movement of the detonator in either direction between the retracted position and the extended position thereof. The plunger 29 may be composed of any suitable material such, for example, as aluminum and having a pair of sleeves 35 of material suitable for the purpose such, for example, as brass secured thereto thereby to facilitate the movement of the plunger within the tubular member 26. The member 26 is also provided with a plurality of apertures 35 thereby to dissipate the force of the explosion of the detonator in the event that the detonator should, for any reason, be prematurely fired before being moved to the extended position and thus the force of the explosion would be ineffective to explode the mine prematurely.

The upper end of the cured to the rack plunger is pivotally se- I5 as by the'bearing screw 31.

The gear 2I is also in meshed engagement with a gear 38 thereby establishing a connection be- IB and a gear train including tween the spring by the screws 61.

an esoapeme mecha sm (n t wn) w y the movem nt i he ea 2 a t e e h mechan m s e rat n, s controlled f eien y t retard the mo m of the plunger 29 and detonating device 3| secured thereto until a pred te mined od of t u h for p e, as 5 seconds after the mechanism I9 has been set in operation, is permitted to elapse before the plun er and detona e ha e o d from the aeted o ition o the ful extend position he eof, When this o urs the ack 5 is onnec d from th gea 2! by the pin engaging the s r 49 as the n tc d p n 5 o the ree s mo e be nd the s ulder 4' o e ppo t secu e to h Plat 9 as by the ew 3- Th esoepemen meohah continues to rerate until sufficient time has elapsed for the mine to corne to rest on the bed of a body of water which a mine is planted at the expiration of this period of time the escapcment mechanism causes an arming switch to be closed, as disclosed in the aforesaid copending application of James B. Qlennon and B gger W. Wallace. Secured to the plate 19 in any convenient manner as by the screws 44 is the inertia controlled safety device 45, the device comprising, among other elements, a supporting plate 45 having two bent up portions 41 within which is slideably supported a l ok n e or o 4 ada t o e v d by a spring 49 within an aperture 5| formed in the member 28 sufficiently to prevent movement of the plunger go into the iully extended position or from the fully extended position toward the retracted position thereoi, as the case may be.

The rod 46 is provided with a sleeve or collar 52 secured thereto and adapted to be engaged by the locking member 59 slideably supported by the projecting portions 54 of the plate 46 when the rod 43 is in the retracted position thereof. There is also arranged on the rod 48 a sleeve or collar 55 composed of suitable insulating material such, for example, as fiber and in abutting relation with respect to the collar 52 when the rod is in the extended position. The collar 55 is preferably in contact with a washer 59 arranged intermediate the collar and the spring 49. The outer end of the rod 48 is preferably enlarged or otherwise formed as at 51 whereby the rod may be retracted manually at will without employing a retracting tool for this purpose thereby providing an arrangement in which, if desired, the mechanism may be readily reset and operated through a plurality of cycles of operations during the adjustment and testing thereof. The collar 55 is provided with a shoulder 58 adapted to engage a contact spring 59 and move the contact spring into engagement with the contact 6| as the rod 48 moves into a locking position with respect to the plunger 29 in response to a violent shock or blow received by the device.

The contact spring 59 is secured to a support 62 in any suitable manner, the support being clamped to a plate 53 of suitable insulating material as by the screws 64. An external electrical connection to the contact spring 59 is established by means of the conductor 65 secured thereto. The plate 6.3 is secured to a base or support 66 as In like manner the contact member BI is secured to the plate 63 as by the screws 68, and 69, an external electrical connection being established to the contact 6! as by the conductor 33 secured thereto and extending to the detonating device 3!. A support 66 is secured to the plate [9 by the nut 12 threaded on the. stud l3 and by the dowel pin 14. The support 66 is provided with a spherical recessed portion 15 adapted to receive and pivotally support a rod '16 at the enlarged spherical shaped portion 1'! thereof, the enlarged portion 11 being retained Within the recessed portion 15 of the support by a cap 18 secured to the support 66 as by the screws l9 thereby providing a ball and socket arrangement for pivotally supporting one end of the rod 16.

The opposite end of the rod 16 is provided with a mass 8! preferably threaded thereon and locked thereto as by the nut 82 in a predetermined adjusted position with respect to the rod 15. The other or outer end of the mass 5| is recessed as at 83, Fig. 3, thereby to receive a protruding portion 64 of the arm of a latch member 85 pivotally mounted on the plate 46 as at 81 and provided with a second arm 83 adapted to move within a slotted portion 89 of the member 26.

The end of the arm 88 is preferably rounded as at 9| and adapted to engage the plunger 29 when the plunger is in the retracted position shown on Fig. l and thereby lock the mass Bl to the projecting portion 84 of the latch member 85 and prevent the premature operation of the inertia switch during the fabrication, handling, and transportation of the mine until the plunger 29 has been moved from the fully retracted position thereof. The member 86 is yieldably urged in a direction of maintain the projecting portion 84 thereof in engagement with the recessed portion of the mass Bl, until a shock or blow of predetermined strength is received subsequent to the movement of the plunger 29 from the retracted position thereof, by a spring 92 secured thereto and having one end in engagement with an adjustable member 93 pivotally supported at 81 and provided with an arcuate portion 94 Within which the screw 44 is disposed. An arrangement is thus provided in which the spring 92 may be adjusted at will by the member 93, and the member 93 clamped in a predetermined setting thereof by the screw 44 corresponding to a blow or shock of re e mine Strength n ces a y to c s he mass 8| to be dislodged from the projecting portion 84 of the latch member 86. As the latch 86 moves into the released position shown on Fig. 2 of the drawings, a cam 95 secured thereto moves out of engagement with one end of the locking member 53 thereby causing the locking member to be disengaged from the collar 52 by the pressure of the spring 95 against a shoulder or collar 91 secured to the locking member.

In the event that this should occur before the plunger 29 moves to a position opposite the end of the rod 48, the rod 48 is moved inwardly by the spring 49 into the path of travel of the plunger thereby preventing the plunger from being moved to the extended position thereof. By arresting the plunger before the notched portion 39 thereof has moved into engagement with the shoulder 4| on the support 42, the rack is prevented from being disengaged from the gear 2| and the gear 38 and. escapement mechanism connected thereto is therefore brought to rest before the foresaid arming contacts of the mechanism l0 are closed. The arming contacts are thus prevented from closing and the mine, therefore, is prevented from being fired and rendered absolutely safe in the event that the mine is accidently dropped or receives a severe blow with the arming plugs removed prior to the launching thereof.

In the event, however, that the mine receives a violent shock or blow after the detonator and plunger 29 have been moved to the fully extended position such, for example, as the shock of impact of the mine against the water when the mine is launched from an aircraft in flight, the release of the rod 38 causes the inner end thereof to move within the path of travel of the plunger 29 supporting the detonator thereby effectively prevent ing the return movement of the plunger and detonator to the retracted position thereof.

As the rod 48 moves inwardly into the member 26 in response to the disengagement of the mass 8! from the latch member 86, the contact spring 59 is moved into engagement with contact 6| thereby closing a circuit from the firing mechanism FM, Fig. 10, by way of conductor 32, detonating device 3!, conductor 33, contacts 6! and 59 of the safety switch, from whence the circuit is continued by way of conductor 65 to the firing mechanism. The firing mechanism FM may be of any type suitable for the purpose in which a firing circuit to the detonator is closed in response to signals picked up by the induction coil 98 connected thereto such, for example, as the firing mechanism disclosed and claimed in the copending application of James B. Glennon et al. for Mine firing mechanism, Serial No. 406,236, filed August 9, 1941.

Briefly stated in summary, the present invention contemplates the provision of a new and improved inertia controlled safety device for use with a mine of the type adapted to be launched from an aircraft in flight in which there is no possibility of operating the safety device until the detonator has been moved from an initial retracted position thereof in response to the detachment of certain safety devices by arming wires respectively connected thereto, and in which the detonator is prevented from being moved into an extended position in operative relation with respect to an explosive booster charge when the mine is subjected to a violent shock during the movement of the detonator toward the extended position thereof, and in which the detonator is locked by an element of the safety device in the extended position when sufficient time has elapsed for the detonator to move into the extended position before the shock is received. The present invention also contemplates the provision of means for maintaining the firing circuit to the detonator continuously interrupted until the shock is received and for closing the firing circuit in part in response to the operation of an inertia controlled element included within the dev1ce.

While the invention has been described in connection with the preferred embodiment thereof which is adapted for the uses set forth in the description, it is to be understood that the reference to such uses shall not limit the invention thereto and that various changes may be made in the mechanism employed within the principles of this invention, and that any words of description that may be imported into the claims from the specification are not to be considered as words of limitation.

The invention herein described and claimed may be manufactured and used by or for the Government of the United States of America for governmental purposes without payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a device of the character disclosed for arming a submarine mine adapted to be released from an aircraft in flight, detonating device adapted to be moved from an initial retracted position to an extended position, a source of power, means adapted to cause the detonating device to be moved by said source of power from said initial position to the extended position, and inertia controlled means for arresting the detonating device during movement thereof to said extended position in response to a shock received during said movement of the detonating device.

2. In an arming device for a mine adapted to be released from'an aircraft in flight, a detonating device, means for moving said detonating device from an initial retracted position to an extended position, and means including an inertia controlled element for preventing the movement of said detonating device to said extended position in response to a shock received during said movement of the detonating device.

3. In a device of the character disclosed for arming a submarine mine adapted to be released from an aircraft in flight, a detonating device, means adapted to move the detonating device from an initial position to an extended position, and inertia controlled means for locking said detonating device in said extended position in response to shock received after the detonating device has been moved to the extended position.

4.'In a device for arming a submarine mine adapted to be released from an aircraft in flight, a detonating device, a slideable support for said detonating device, means for moving the detonating device and the support from an initial retracted position to an extended position, an inertia controlled safety device, a firing circuit for, said detonating device, means on said safety device for closing in part said firing circuit as the safety device operates in response to a shock received after the detonating device has moved away from said initial position, and means controlled by said support for preventing the operation of the safety device in response to a shock received before the support has moved away from said initial position. 1

5. In an arming device for a mine adapted to be launched from an attacking craft, a detonating device, means for moving said detonating device from an initial retracted position to an extended position, means including an inertia controlled element for preventing the movement of said detonating device to said extended position in response to a shock received by said element during said movement of the detonating device, means including a resilient member for releasably supporting said inertia element in an initial set position, and means for adjusting said resilient member to different settings corresponding respectively to diiferent degrees'of force required to release said inertia element from said supporting means.

6. In an arming device for a mine adapted to be launched from an attacking craft, a detonating device, means for moving said detonating device from an initial retracted position to an extended position, means including an inertia controlled element for preventing the movement of said detonating device to said extended position in response to a shock received by said element during said movement of the detonating device,

means including a resilient member for releasably supporting said inertia element in an initial set position, means including a pivoted member setta'ole at will to different settings, and means, for locking said pivoted member in any of said settings. i

'7. In a device of the character disclosed for arming a submarine mine adapted to be released from an aircraft in flight, a detonating device, means for moving said detonating device from a retracted position to an extended position, a slideable bar adapted to be moved within the path of travel of said detonating device, means for yieldably urging said slideable bar toward said path of travel, a moveable latch dapted-to maintain said slideable bar releasably in an initial cocked position out of said path of travel, means for yieldably urging said latch out of engagement with said slideable bar, a rotatable cam element adapted to maintain said latch in operative engagement with said slideable bar selectively in accordance with the instant setting of the cam, means for yieldably urging said cam element'toward a. released position with respect to said latch, an arm on said cam member, and a pivoted inertia member in releasable engagement with said arm adapted to prevent the disengagement of the latch from said slideable bar until the inertia element is disengaged from the arm by a predetermined force of deceleration applied thereto.

8. In a device of the character disclosed for arming a mine, in combination, a tubular member an electroresponsive detonating device, a support for said detonating device slideably disposed within said tubular member and adapted to be moved from an initial retracted position to an armed position, means for actuating said detonating device, said tubular member having an aperture transversely arranged therein, a safety device comprising a slideable bar having one end thereof disposed within said aperture and adapted to be moved into the path of travel of said support as the safety device operates, means including a pivotally supported mass for operating said safety device in response to a predetermined force of deceleration applied thereto, circuit closing means adapted to be operated by said slideable bar for closing in part a circuit to said detonating device, and means including a pivoted member having an arm disposed within said tubular member and in substantial abutting relation with said support for preventingthe operation of said safety device until the detonating device has moved away from said retracted position within said tubular member.

9. In a, safety device for a mine, in combination, a detonator, means for moving said detonator from a safe position to an armed position, a slideable locking bar adapted to prevent movement of said detonator into said armed position as the bar operates, bar operating means, a shoulder on said bar, a slideable pin adapted to engage said shoulder and prevent movement of the bar until the pin operates, and means including an inertia element for causing said pin to be moved out of operative engagement with said shoulder in response to a shock of predetermined strength received by the inertia element thereby to cause said locking bar to arrest the detonator during movement thereof toward said armed position.

10. In a safety device of the character described for a mine, a detonator adapted to be moved to a safe position and to an armed position respectively, means for moving said detonator, an inertia controlled device having a movable member adapted to lock the detonator in said 10 included within said firing circuit and controlled by said movable member for maintaining the firing circuit continuously interrupted until said safety device operates.

11. In a safety and arming device of the character disclosed, in combination, mine firing means, an electroresponsive detonator, a movable support for said detonator, means for actuating said detonator support from an initial retracted position to an extended position, a firing circuit for said detonator, an inertia controlled switch adapted to close in part said mine firing circuit as the switch operates in response to a shock received by the mine, and means controlled by said detonator support for preventing the operation of said inertia switch until the support has moved away from said retracted position.

12. In an arming device for a mine adapted to be released from an aircraft in flight, a detonating device, means for moving said detonating device from an initial retracted position to an extended position, a slideable rod, means for yieldably urging said slideable rod into the path of travel of said detonating device, a, second slideable rod adapted to be moved to a locking position and to a released position respectively, means on the first named slidable rod adapted to be engaged by said second slideable rod sufiiciently to prevent movement of the first slideable rod into the path of travel of said detonating device, a pivoted inertia controlled element, and a, cam on said inertia controlled element adapted to actuate said second slideable rod into locking engagement with said shoulder and into a released position with respect thereto selectively in accordance with the instant setting of said pivoted inertia controlled element.

13. In a safety device for a mine, the combination of a slideable locking member, resilient means for actuating said member, a, moveable latch adapted to restrain said member releasably in an initial position, resilient means for actuating said latch, a pivoted cam member adapted to control said latch, resilient means for actuating said cam member, and a pivoted inertia member in releaseable engagement with said cam member for preventing movement of the cam member until the inertia member has been released therefrom in response to a shock of predetermined strength received by the inertia member.

14. In an arming device for a mine adapted to close an arming circuit at the completion of an arming cycle thereof, a detonating device, means for moving said detonating device to an armed position during said arming cycle, and means including an inertia controlled element for arresting the movement of said detonating device toward said armed position in response to a shock received during said movement thereby to prevent the completion of said arming cycle.

JAMES B. GLENNON. ROGER W. WALLACE. BERNARD WOODWARD, JR.

REFERENCES CITED The following references are of record in the file of this patent:

safe position as the inertia device operates in response to a shOck received by the mine, mine firing mechanism, a firing circuit from said mine firing mechanism to said detonator, and means UNITED STATES PATENTS Number Name Date 2,236,872 Grigsby Apr. 1, 1941 2,351,607 Grant et al June 20, 1944 

